1. Field of the Invention
This invention relates to a ventilating device for a container, comprising a container frame consisting of tubular rail members, outer ventilation holes formed through the outer wall of the rail member so as to be exposed to the outside of the container, inner ventilation holes formed through the inner wall of the rail member so as to be exposed to the interior of the container, and a ventilation channel formed inside the rail member so as to communicate the outer and inner ventilation holes.
2. Brief Description of the Prior Art
Demands for transporting perishables such as cereal or fruit with containers are increasing. Such perishables tend to rot due to excessive moisture by aspiration of these perishables or due to condensation caused by temperature difference between inside and outside of a container. For these reasons, an increase in the capacity of a ventilating device for a container is desired.
However, problems arise if holes are simply formed on the outer surface of a container. For example, a marine container (that is, a container transported by a container ship) is subject to splashes of sea water as well as rain water. Such water may easily flow into the container and may damage the goods held therein.
In order to increase the amount of ventilation, ventilating devices for a container as shown in FIGS. 1A and 1B have been proposed. In these ventilating devices, the interiors of a top rail 1 and a bottom rail 2 comprising tubular rail members define ventilation channels.
A ventilation channel 3 of a ventilating device of these types has a configuration as shown in FIG. 1A or 1B. In the ventilation channel 3 shown in FIG. 1A, drain plates 6 project inward in a staggered manner from inner and outer walls 4 and 5, respectively. In the ventilation channel 3 shown in FIG. 1B, a drain plate 7 projects from an inner wall 4, where the drain plate 7 is bent at its intermediate portion and has an opening 11. Ventilation air is introduced from the outside to the interior of the container through outer ventilation holes 8, the ventilation channel 3 and inner ventilation holes 9. The ventilation air makes a detour or collides against the drain plate 6 or 7, so that moisture may be satisfactorily removed therefrom.
However, since the drain plate 6 or 7 is mounted on the rail member 1 or 2 by welding, rivetting or the like, narrow corners or gaps are formed at the mounting portions. Dust and the like tend to deposit in these corners, and the deposited material becomes dampened.
This causes rusting or formation of mildew to shorten the service life of the container. In addition to this, these corners or gaps are hard to clean, presenting the problem of bad hygiene condition, especially in the case of containers for transporting perishables.
Furthermore, in the case as shown in FIG. 1A wherein the drain plates 6 are inclined, even if fastening members 10 are loosened to remove the inner wall 4, the lower surfaces of the drain plates 6 mounted on the outer wall 10 are hard to inspect. On the other hand, in the case as shown in FIG. 1B wherein the drain plate 7 is bent inward, the bent portion of the drain plate 7 is similarly hard to inspect. In either case, if the rail members 1 and 2 are subjected to a surface treatment, the problems of quality control are apt to occur as well as the cleaning and inspecting problems as mentioned above.
In the cases shown in FIGS. 1A and 1B, the drain plates 6 and 7 must be prepared separately from the rail members 1 and 2 and must then be fixed thereto by welding or rivetting. This results in a larger number of parts and complex mounting procedures. The structures shown in FIGS. 1A and 1B are, therefore unsuitable for mass-production.